Synthetic hair extensions and methods for making the same

ABSTRACT

A method for making synthetic hair extensions is provided. According to the method, raw material including polypropylene resin is mixed, the raw material is extruded to produce polypropylene yarn, some of the polypropylene yarn is formed into a hank, the ends of the yarn are pressed between the sheets of a press such that the ends abut a lip of one of the sheets, and the hank of yarn with the press is passed through a conveyor furnace to relax the yarn. Also provided is a mixture for extrusion into polypropylene yarn. The mixture comprises polypropylene resin, 2-8% magnesium stearate, 3-8% dye, and optionally 1-4% flame retardant (percentages by weight relative to weight of polypropylene resin).

FIELD OF THE INVENTION

The present invention generally relates to hair extensions, and morespecifically to synthetic hair extensions and methods for making thesame.

BACKGROUND OF THE INVENTION

In general, hair extensions are additional hair that is used to addvolume, length, and depth to a natural hairline. Braiding, bonding andweaving, and hair extension clip-ins are some popular hair extensionmethods. Depending on the wearer's requirements, budget, and hair typeand length, hair extensions are typically chosen after consulting a hairexpert. Hair extensions are safe and trusted by women all over the worldfor solving issues related to thinning hair, hair loss, and evenbalding. Women of any age can use hair extensions.

In the past, there were only human hair extensions made of real humanhair. These human hair extensions are expensive and their availabilityis limited. As a result, the use of human hair extensions was limited tothe wealthy and famous. Now there has been developed another type ofhair extension—synthetic hair extensions that are manufacturedartificially.

With the advent of synthetic hair extensions, the cost has decreased andthe availability has increased. As a result, hair extensions are nowcommonly worn by people from every walk of life and of every nationalityand race.

Human and synthetic hair extensions each have advantages anddisadvantages, and can be differentiated on such factors as price,longevity, styling, maintenance, and feel. For example, human hairextensions look natural and real, can be colored and styled withoutrestrictions, and are long lasting. However, human hair extensions aremore expensive than synthetic extensions, require constant care andattention like real human hair, and can be sourced in an unhygienicmanner. Synthetic hair extensions advantageously do not requiretreatments like deep conditioning, are less expensive than humanextensions, and have the ability to add more volume. But conventionalsynthetic hair extensions typically are distinguishable from human hair,have an unnatural feel, break easily, and are difficult to incorporateand style.

In view of the foregoing, improved synthetic hair extensions are needed.In particular, what is needed are synthetic hair extensions that feeland look like human hair, that are stronger, and that are soft andsmooth to the touch, along with methods for making the same.

SUMMARY OF THE INVENTION

One embodiment of the present invention provides a mixture for extrusioninto polypropylene yarn. The mixture comprises polypropylene resin, 2-8%magnesium stearate, and 3-8% dye (percentages by weight relative toweight of polypropylene resin). The mixture optionally also comprises1-4% flame retardant.

Another embodiment of the present invention provides a method for makingsynthetic hair extensions. According to the method, raw materialincluding polypropylene resin is mixed, the raw material is extruded toproduce polypropylene yarn, some of the polypropylene yarn is formedinto a hank, the ends of the yarn are pressed between the sheets of apress such that the ends abut a lip of one of the sheets, and the hankof yarn with the press is passed through a conveyor furnace to relax theyarn.

Other objects, features, and advantages of the present invention willbecome apparent from the following detailed description. It should beunderstood, however, that the detailed description and specificexamples, while indicating preferred embodiments of the presentinvention, are given by way of illustration only and variousmodifications may naturally be performed without deviating from thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart showing a process for making synthetic hairextensions according to one embodiment of the present invention;

FIG. 2 shows an exemplary melt spinning process;

FIG. 3 shows a polypropylene yarn production machine that is used in oneembodiment of the present invention;

FIGS. 4A and 4B show a press that is used in one embodiment of thepresent invention;

FIG. 5 shows a drum tumbler that is used in one embodiment of thepresent invention;

FIG. 6 shows a side view of an upper portion of the polypropylene yarnproduction machine;

FIG. 7 shows a perspective view of the polypropylene yarn productionmachine;

FIG. 8 shows spinnerets of the polypropylene yarn production machine;

FIG. 9 shows winder heads of the polypropylene yarn production machine;

FIG. 10 shows the oil dispenser of the polypropylene yarn productionmachine;

FIGS. 11 and 12 show the use of a skein winder in one embodiment of thepresent invention;

FIGS. 13-15 show the use of the press in one embodiment of the presentinvention;

FIG. 16 shows a fiber relaxation tunnel that is used in one embodimentof the present invention;

FIGS. 17 and 18 show hanks that have passed through the fiber relaxationtunnel;

FIGS. 19 and 20 show hanks after rest periods;

FIGS. 21 and 22 show hanks after being brushed; and

FIG. 23 shows synthetic hair extensions produced according to a processfor making synthetic hair extensions according to an exemplaryembodiment of the present invention.

DETAILED DESCRIPTION

As required, embodiments of the present invention are disclosed herein;however, it is to be understood that the disclosed embodiments aremerely examples and that the systems and methods described below can beembodied in various forms. Therefore, specific structural and functionaldetails disclosed herein are not to be interpreted as limiting, butmerely as a representative basis for teaching one skilled in the art tovariously employ the present subject matter in virtually anyappropriately detailed structure and function. Further, the terms andphrases used herein are not intended to be limiting, but rather, toprovide an understandable description of the concepts.

Embodiments of the present invention provide improved synthetic hairextensions and methods for making the same. The improved synthetic hairextensions look and feel like human hair, and blend seamlessly withhuman hair. They are strong but soft and smooth to the touch. Theimproved synthetic hair extensions also provide many benefits to hairstylists such as saving time, lowering waste, and increasing revenuesbecause they are tangle free and trimming free.

FIG. 1 is a flowchart showing a process for making synthetic hairextensions according to one embodiment of the present invention. In thisexemplary embodiment, polypropylene resin is first mixed with other rawingredients 101 and then the mixture is run through an extruder to makepolypropylene yarn 102. The polypropylene yarn is grouped into hanksthat are each secured and cut 103. Next, the hanks of yarn go through arelaxation tunnel 104 and then are rested 105. After sufficient resting,the resulting fibers are brushed to produce the desired hairstyle 106,and then packaged for sale 107. The brushing can be performed manuallyby a person or automatically by an electronic (electronically-controlledor computerized) brushing machine.

In this exemplary embodiment, the polypropylene resin is acommercially-available polypropylene pellet resin known as Esenttia18H86 from Esenttia (of the Ecopetrol Business Group) and supplied byPolipropileno del Caribe S.A. This is a medium melt flow ratepolypropylene homopolymer having high cleanness and stableprocessability, good tenacity/elongation balance, gas fading resistance,and excellent whiteness. In further embodiments, other polypropyleneresins are used. In yet other embodiments, nylon or polyester resins areused in place of polypropylene.

In this exemplary embodiment, the Esenttia 18H86 polypropylene pelletresin is mixed with magnesium stearate at 4%, dye at 6%, and flameretardant at 1-2% (percentages by weight relative to weight ofpolypropylene pellet resin). In further embodiments, other relativepercentages of these products are used in the mix, as shown by theranges in Table 1. Preferably, 50 kg of polypropylene pellet resin isused for each batch, but a batch size of 25-200 kg of polypropylenepellet resin is possible in this embodiment. And other batch sizes arepossible in embodiments that use other extruding equipment.

TABLE 1 Min. Max. Preferred Magnesium Stearate 2% 8% 4% Dye 3% 8% 6%Flame Retardant 1% 4% 2%

The magnesium stearate is added to give the resulting fiber greaterweight and rigidity, and the dye is used to produce the desired haircolor. In one embodiment, the flame retardant is contained in a productknown as CESA TH-LIGHT/FR PPA0606535 from Clariant International Ltd.This is a CESA masterbatch product that combines a flame retardant withother additives for providing thermal and UV light stability. Theproduct is a concentrate in pellet form containing a mixture ofhalogenated compounds for flame retardation and light stabilizers in apolypropylene base resin. In this embodiment, pellets of the CESAmasterbatch product are added to the polypropylene pellet resin at 1-4%,and preferably at 2%. In further embodiments, any suitable flameretardant that inhibits or prevents combustion of the plastic can beadded to the polypropylene pellet resin at 1-4% (and preferably at 1-2%or 2%), with the addition of thermal and/or UV light stabilizers beingoptional.

In this exemplary embodiment, the polypropylene pellet resin, magnesiumstearate, dye, and flame retardant are placed into a drum and then mixedby a motorized drum tumbler for 15 minutes at ambient temperature (e.g.,15° C.-25° C.) to produce a homogeneous compound. As shown in FIG. 5,the drum tumbler 502 is a machine that automatically mixes theingredients by rotating one or more of the drums 504. In furtherembodiments, the mixing is performed for 10-25 minutes at a temperatureof 10° C.-30° C. (preferably about 20° C.).

The polypropylene pellet resin mixture is then run through an extruderthat uses a melt spinning process to produce polypropylene yarn. FIG. 2shows an exemplary melt spinning process. The polypropylene pelletmixture is fed into a feed hopper 201. The mixture is melted and then amelt spinning pump 202 forces the molten material through the orificesof a spinneret 203. A gear pump is used to press the molten materialthrough the spinneret at a constant rate. After exiting the spinneret,the molten filaments enter a quench air duct 204 a short distance (e.g.,5-20 cm) below the spinneret and are solidified by the air. Afterleaving the quench air duct, the filament bundle is drawn over one ormore godets (rollers) 205 and then wound on spinning packages 206.

In this exemplary embodiment, the extruder is a high/medium-tenacitypolypropylene yarn production machine such as the Austrofil HT/MTMultifilament Spinning Plant (e.g., Austrofil HT 2×2 C, model 2005) madeby SML Maschinengesellschaft mbH of Lenzing, Austria. FIG. 3 shows afront view of the polypropylene yarn production machine, FIG. 6 shows aside view of an upper portion of the machine, and FIG. 7 shows aperspective view of the machine. The specifications of the polypropyleneyarn production machine are shown in Table 2. The polypropylene pelletresin mixture is fed into the feed hopper 301 and extruded at a melttemperature of 220° C. (428° F.). In further embodiments, extrusion isperformed at a melt temperature of 190° C.-230° C. Following extrusion,the molten material is optionally pressed through a screen belt filterto remove impurities and provide consistent quality.

Then spinning pumps in the electrically heated spinning beam press themolten material with steady and sufficient pressure through four48-strand spinnerets 302 so as to produce filaments 308 having afilament diameter of 0.6 mm. Two of the spinnerets of the polypropyleneyarn production machine are shown in FIG. 8. In further embodiments, afilament diameter of 0.4-0.9 mm is used. Upon emerging from thespinnerets 302, the filaments 308 are cooled by a controlled air streamin a quench air duct 303. The filaments are then supplied with spinfinish and drawn off to one or more stretching modules 304 via godets(rollers).

In this embodiment, the filaments 308 from each spinneret 302 aresupplied to a stretching module 304 that draws them over three pairs ofstretching godets 309. This facilitates stretching ratios of up to 1:8.Optionally, a hot air chamber is provided in the stretching module toincrease yarn tenacity. The yarn is then intermingled and wound ontobobbins by one or more winder heads 310. Two winder heads of thepolypropylene yarm production machine of this embodiment are shown inFIG. 9. This extrusion process produces a continuous final fiber havinga denier of 1,700, a tenacity of 2.20 cN/den (2.24 g/den), and 50%stretching or elongation. In further embodiments, the final fiber hasdenier of 1530-1870, a tenacity of 1.98-2.42 cN/den, and 30%-60%stretching or elongation.

During extrusion, the filaments 308 are preferably lubricated withextrusion oil by an oil dispenser 312 on the extruder in order to makethe resulting yarn easier to work with during subsequent processing. Theportion of the polypropylene yarn production machine that performs thelubrication is shown in FIG. 10. In this exemplary embodiment, 100 kg ofLubristat “PNP-NA” (available from Cempri S.A.S. of Bogotá, Colombia) ismixed with 100 kg of water until the mixture is homogenized(approximately 15 minutes). The oil mixture is then supplied to areservoir on the extruder. During extrusion, a pump delivers the oilmixture to the oil dispenser 312, which lubricates the filaments 308with the oil mixture during the final cooling in which the yarn becomessolid. The dose rate is 3% oil mixture (for example, 100 kg of extrudedfilament contains 97 kg of the polypropylene mixture and 3 kg of theoil-water mixture). Lubristat PNP-NA is a lubricant for synthetic fibersthat provides lubrication, static control, and cohesion of the fiber, inaddition to an excellent touch. These properties are important forobtaining good performance of the yarn during the subsequent processingstages. This lubricant is also easily removable by a conventional wash.In further embodiments, the ratio of oil to water can differ, and thedose rate can also differ (e.g., 1-4% oil mixture, preferably 2% or 3%).

TABLE 2 Raw Material polypropylene homopolymer MFR (230/2.16) (ISO1133), 10-35 g/10 min Capacity 160 kg/h Raw Material Resin hopper withsuction feeder Handling Extrusion Extruder diameter: 75 mm L/D ratio: 28Max. screw speed: 160 rpm Melt Filtration incl. static mixer optionalcontinuous melt filtration with SML screen belt Spinning Beam Number ofspinning pumps: 4 Number of spinning packages: 8 Stretching Number ofstretching units: 1-4 Threads per drawing unit: 2 (4) Draw ratio:infinitely variable Winding Number of winder heads: 1-4 Threads perwinder: 1/2/4 Core inner diameter: 75 mm (84 mm) Bobbin diameter:300-420 mm Compressed Air Compressor pressure: 7.5 bar Supply Avg. airconsumption (incl. intermingling): 550 Nm³/h Peak air consumption: 1000Nm³/h Water Chiller approx. 63,000 kcal/h Cooling Capacity

The bobbins of yarn are then processed and finished to produce synthetichair extensions. In particular, a skein winder 1102 is used to roll theyarn, as shown in FIG. 11. The yarn is grouped and cut into hanks (loopsof yarn) 1202 of 90 grams, which are each secured (e.g., tied by a tie1204) to prevent the fibers from becoming tangled or separated, as shownin FIG. 12. Each hank 1202 is cut in the middle and then the resultingends (tips) of the fibers are clipped in a custom press 1206, as shownin FIG. 13.

The custom press 1206 used in this exemplary embodiment is shown in atop view in FIG. 4A and in a side view in FIG. 4B. The press 1206 isformed by two flat sheets of cold rolled aluminum 1208 and 1210 heldtogether by a clip 1212 that is riveted 1214 to each of the sheets. Inthis exemplary embodiment, the top aluminum sheet 1208 is 8″ long by 1⅜″wide and the bottom aluminum sheet 1210 is 8″ long by 1½″ wide. The backedge 1211 of the bottom sheet 1210 is turned up to form an “L”-shape(i.e., lip) that is sized so as to be flush with the top sheet 1208 whenthe sheets are pressed together by the clip 1212.

As shown in FIGS. 14 and 15, the top and bottom sheets 1208 and 1210 areseparated and the cut fibers of the hank 1202 are inserted into thepress 1206 such that their ends 1203 abut the lip 1211 of the bottomsheet 1210. The two sheets 1208 and 1210 are then clipped onto thefibers such that the two sheets are substantially parallel and generatepressure on the end portions 1205 of the fibers that are clipped(enclosed) in the press. The dimensions of the press are designed sothat it holds a set length of the end portions 1205 of the fibers whilebeing able to pass through the furnace without getting stuck. Whilealuminum allows for good heat regulation, the sheets are made of anothermaterial such as stainless steel in further embodiments. Additionally,the sheets have different dimensions in further embodiments (e.g., widthincreased to hold a greater length of the end portions in the press).

The secured and cut hanks of yarn with the press applied are then runthrough a fiber relaxation tunnel 1602, which is a specially-designedconveyor furnace as shown in FIG. 16. A conveyor belt moves each hank ofyarn through the furnace tunnel for six minutes. A series of resistancesheat the inside of the tunnel to a temperature of 135° C. (275° F.). Infurther embodiments, this relaxation process is performed at atemperature of 110° C.-150° C. for 2-12 minutes. However, it has beenfound that the best results are obtained at approximately 135° C. forapproximately 6 minutes. In this embodiment, three fans keep the airconstantly moving inside the tunnel to guarantee that a steadytemperature is maintained during the trip through the tunnel. The heatand constantly moving air inside the tunnel at least partially evaporatethe extrusion oil so that the fibers are relaxed and tension isreleased. Additionally, they relax and contract the fibers so as toproduce a thread that detaches properly when being brushed so that thenecessary volume can be obtained.

FIGS. 17 and 18 show hanks that have passed through the relaxationtunnel. Because the end portions of the fibers are clipped in the presswhen passing through the tunnel, the fibers remain oriented and the tips(ends) of the fibers do not contract or deform in the tunnel. The pressholds and presses the end portions of the fibers during passage throughthe furnace so that the temperature of the furnace does not act directlyon this portion of the fibers. The end result is uneven, naturallooking, and softer tips (ends) than the rest of the fibers. Thisproduces extensions with tips having an almost natural finish thatresembles human hair. When removing the press after exiting the tunnel,the end portions are straight (ironed) and look like natural human hairbecause they have an uneven and natural finish. And the resulting tipsare smooth because the press prevents or reduces entanglement of thefibers. This facilitates the making of braids, hair styling, and finalfinishing. The relaxation tunnel (along with the press) provides a muchbetter product as compared to conventional processes that afterextrusion pass the thread through rollers with teeth that grind thethread so as to cause irregularities and then comb the cuffs to obtainthe volume.

After a hank leaves the relaxation tunnel, the press that holds the endportions is removed and the hank is hung from its middle (e.g., by thetie). The resulting tips are self-ironed (smooth). The hanging fibersrest at ambient temperature (e.g., 15° C.-25° C.) for 24 hours. In onepreferred embodiment, rest is at an average temperature of 18° C. (64°F.). During the resting time, the fibers are cooled, relaxed, andextrusion oil is evaporated. This allows the fibers to finishcontracting and releasing tension, as shown in FIGS. 19 and 20. Afterthis rest period, the fibers have the desired final volume and texture.In further embodiments, this resting process is performed for 16-30hours at a temperature of 10° C.-30° C.

After resting, the fibers in the hank are brushed to style the hair.This brushing can be performed manually (i.e., by hand), orautomatically by a brushing machine. This orients the fibers andseparates their filaments to provide volume, functionality, and anatural texture. After being brushed, the fibers acquire a volume andnatural finish that makes the hair look like human hair and soft to thetouch, as shown in FIGS. 21 and 22. In some embodiments, automatedequipment is used to brush the hair extensions.

The resulting synthetic hair extensions are then packaged in a paperinsert that contains color information, length measurement, advantages,and qualities, as shown in FIG. 23. The paper insert and synthetic hairextension are then placed in a plastic sleeve for preservation.

Accordingly, embodiments of the present invention provide improvedsynthetic hair extensions and methods for making the same. Thesesynthetic hair extensions feel and look like human hair, and blend wellwith human hair. It is difficult to tell the difference between thesynthetic hair extensions and human hair. The synthetic hair extensionsare not deformable, which makes them resistant. Additionally, thesynthetic hair extensions are very soft and extremely smooth to workwith. They will not cut fingers, which is very important because thehands are a professional's primary working tool. And the user benefitsfrom having a full head of hair. And the softness of the synthetic hairextensions reduces or prevents headaches caused by tightly pulledponytails or braids.

Further, due to its tenacity property, the synthetic hair extensions arestronger and thus extremely functional. For this reason, the synthetichair extensions of the present invention will completely change the waythe hair stylist does braids. The synthetic hair extensions are tanglefree, trimming free, waste free, easy to separate, easy brushing, easyto handle, and do not break. These benefits save time when making a fullinstallment of hair extensions. This allows the user to leave earlierand go back to daily activities, and allows the hair stylist to increaserevenue and have time for additional customers per day.

The synthetic hair extensions of the present invention are particularlysuited for easily creating fancy fashion African-American-style braidsand the most well-known African-American-style braids.

The terms “a” or “an”, as used herein, are defined as one or more thanone. The term plurality, as used herein, is defined as two or more thantwo. The term another, as used herein, is defined as at least a secondor more. The terms “including” and “having,” as used herein, are definedas comprising (i.e., open language). The term “coupled,” as used herein,is defined as “connected,” although not necessarily directly, and notnecessarily mechanically.

All references cited herein are expressly incorporated by reference intheir entirety. It will be appreciated by persons skilled in the artthat the present invention is not limited to what has been particularlyshown and described herein above. In addition, unless mention was madeabove to the contrary, it should be noted that all of the accompanyingdrawings are not to scale. There are many different features to thepresent invention and it is contemplated that these features may be usedtogether or separately. Thus, the present invention should not belimited to any particular combination of features or to a particularapplication. Further, it should be understood that variations andmodifications within the spirit and scope of the present invention mightoccur to those skilled in the art to which the present inventionpertains. Additionally, an embodiment of the present invention may notinclude all of the features described above. Accordingly, all expedientmodifications readily attainable by one versed in the art from thedisclosure set forth herein that are within the scope and spirit of thepresent invention are to be included as further embodiments of thepresent invention.

What is claimed is:
 1. A mixture for extrusion into polypropylene yarn, the mixture comprising: polypropylene resin; 2-8% magnesium stearate; and 3-8% dye (percentages by weight relative to weight of polypropylene resin).
 2. The mixture of claim 1, wherein the mixture further comprises 1-4% flame retardant.
 3. The mixture of claim 1, wherein the mixture comprises: 4% magnesium stearate; and 6% dye (percentages by weight relative to weight of polypropylene resin).
 4. The mixture of claim 3, wherein the mixture further comprises 1-2% flame retardant.
 5. A mixture for extrusion into polypropylene yarn, the mixture comprising: polypropylene resin; 8% or less magnesium stearate; 8% or less dye; and 4% or less flame retardant (percentages by weight relative to weight of polypropylene resin).
 6. A method for making synthetic hair extensions, the method comprising: mixing raw material that includes polypropylene resin; extruding the raw material to produce polypropylene yarn; forming some of the polypropylene yarn into a hank; clipping ends of the yarn in the hank in a press, the press including a first flat sheet and a second flat sheet with a lip, the ends of the yarn being pressed between the first and second sheets and abutting the lip; and passing the hank of yarn with the press through a conveyor furnace to relax the yarn.
 7. The method of claim 6, further comprising: resting the hank of yarn by hanging; and brushing the yarn to style the synthetic hair extensions.
 8. The method of claim 7, wherein the brushing of the yarn comprises manually brushing the yarn to style the synthetic hair extensions.
 9. The method of claim 7, wherein the brushing of the yarn comprises automatically brushing the yarn with a brushing machine to style the synthetic hair extensions.
 10. The method of claim 6, wherein the resting of the hank of yarn comprises resting at a temperature of 15° C.-25° C. for at least 24 hours.
 11. The method of claim 10, wherein the resting of the hank of yarn comprises resting at an average temperature of 18° C.
 12. The method of claim 6, wherein the resting of the hank of yarn comprises resting at a temperature of 10° C.-30° C. for 16-30 hours.
 13. The method of claim 6, wherein the extruding of the raw material produces polypropylene yarn having a denier of 1,700 and a tenacity of 2.20 cN/den.
 14. The method of claim 13, wherein the extruding of the raw material produces polypropylene yarn having 50% stretching or elongation.
 15. The method of claim 6, wherein the extruding of the raw material produces polypropylene yarn having a denier of 1530-1870 and a tenacity of 1.98-2.42 cN/den.
 16. The method of claim 15, wherein the extruding of the raw material produces polypropylene yarn having 30%-60% stretching or elongation.
 17. The method of claim 6, wherein the passing of the hank of yarn through the conveyor furnace comprises: using a conveyor belt to pass the hank of yarn with the press through a tunnel of the conveyor furnace; using at least one resistance to generate heat inside the tunnel; and using fans to move air inside the tunnel.
 18. The method of claim 6, wherein in the passing of the hank of yarn through the conveyor furnace, the conveyor furnace is at a temperature of 110° C.-150° C. and the hank of yarn takes 2-12 minutes to pass through the conveyor furnace.
 19. The method of claim 6, wherein the extruding of the raw material comprises lubricating the polypropylene yarn with oil.
 20. The method of claim 19, wherein the lubricating of the polypropylene yarn with oil comprises dosing the polypropylene yarn with an oil-water mixture at a dose rate of 1-4% (percentage by weight relative to weight of polypropylene yarn). 